Tyrone wrote:
Anybody ever heard of someone using a device to see underwater while
kayaking? Like a reverse periscope? It could be as simple as a oysterbox /
waterscope (water proof box with a glass bottom). I can't find any mention
of the idea on countless google searches but it seems like it would be a
really useful thing no?

A diving mask or goggles and the ability to roll are all the periscope
one needs. ;-)